Indexing mechanism using pairs of radially disposed rollers engaged between adjacent cam ribs

Abstract

A roller gear cam index mechanism including a turret having pairs of adjacent rollers radially arranged on a circumference thereof. Each pair of rollers is engaged between adjacent ribs on a globoidal cam. The angle between the line up direction of every pair of rollers and the tangent direction of the turret circumference is a variable between 0 to 90 degrees. The rollers are modified globoidal rollers which are selected having difference maximum radii and vertex positions.

What we claim is: 
     
       1. An indexing mechanism, comprising: a rotatable cam;   a plurality of ribs extending from said cam, two adjacent ribs defining a groove therebetween;   a turret member; and   a plurality of rollers spaced circumferentially about said turret member, said rollers being arranged on said turret member in roller pairs, each roller pair being circumferentially offset about said turret member from adjacent roller pairs, and said roller pairs and said groove being operationally dimensioned and arranged such that said roller pairs are received in said groove.   
     
     
       2. The indexing mechanism defined in claim 1, wherein: an outer portion of each roller in said roller pair respectively engages a side wall of each rib defining said groove, and   interior portions of each roller in said roller pair are adjacent and not engaged with any portion of said ribs.   
     
     
       3. The indexing mechanism defined by claim 1, wherein: outer portions of each roller in said roller pair disposed in said groove contacts a sidewall of each curved rib, respectively, and   inner portions of each roller in said roller pair disposed in said groove do not contact any portion of said curved ribs thereby allowing each roller in said roller pair disposed in said groove to move independently under the influence of said outer portions respectively contacting said sidewall of each curved rib.   
     
     
       4. The indexing mechanism defined by claim 3, wherein: said rollers are cylindrical rollers.   
     
     
       5. The indexing mechanism defined by claim 4, wherein: at least two of said rollers are modified globoidal rollers having different maximum radius and vertex positions.   
     
     
       6. The indexing mechanism defined by claim 5, wherein: each modified globoidal roller contacts sidewalls of said ribs at a different contact points due to said different maximum radius and vertex positions of said modified globoidal rollers.   
     
     
       7. The indexing mechanism defined by claim 3, wherein: said rollers are globoidal rollers.   
     
     
       8. The indexing mechanism defined by claim 3, wherein: at least one of said rollers is a modified globoidal roller.